CA2063691C

CA2063691C - Method and apparatus for the ambulatory detection and diagnosis of the sleep apnea syndrome

Info

Publication number: CA2063691C
Application number: CA002063691A
Authority: CA
Inventors: Peter Griebel
Original assignee: MAP Medizintechnik fuer Arzt und Patient GmbH and Co KG
Current assignee: MAP Medizintechnik fuer Arzt und Patient GmbH and Co KG
Priority date: 1991-03-22
Filing date: 1992-03-20
Publication date: 1999-01-12
Anticipated expiration: 2012-03-20
Also published as: CA2063691A1; DK0504945T3; FI921203A; GR3026314T3; DE4138702A1; HK1005057A1; CZ289547B6; EP0504945B1; HU9200934D0; US5275159A; NZ242052A; ES2111007T3; AU1309392A; DE59209049D1; AU649317B2; HU215223B; EP0504945A3; EP0504945A2; FI921203A0; JPH05200031A

Abstract

A method and an apparatus are described for the ambulatory detection and diagnosis of the sleep apnea syndrome, in which the physiological parameters of heart rate, respiratory and snoring sounds, the degree of oxygen saturation of the blood and the bodily position of the patient are measured and stored in coded form by means of a mobile apparatus. The stored data are transferred to a computer and then analyzed.
The mobile apparatus comprises a detection and storage unit and the following pickups: three EKG electrodes, one laryngeal microphone, an oximeter finger sensor and a position pickup. The apparatus according to the invention permits an ambulatory diagnosis of sleep apnea, which is comparable in its meaningfulness to diagnoses based on stationary sleep laboratory tests.

Description

The invention relates to a method for the ambulatory detection and diagnosis of the sleep apnea syndrome, in which the physiological parameters of pulse rate, breathing sounds and snoring sounds of a 5 patient are detected and a number of sets of the parameters that are detected during brief intervals are stored in coded form in a mobile apparatus, transferred to a computer, and analyzed by the latter, and especially variations of the individual parameters in time and correlations between the various parameters are taken into account. The invention furthermore relates to an apparatus necessary for the practice of this method.
The symptom of sleep apnea is characterized by a combination of a respiratory failure, a considerable hypoxemia (i.e., a reduction of the oxygen content in the arterial blood) and heart rhythm disturbances.
After an episode of apnea, a severe gasping for air and often also a terrifying awakening occur as a rule (see, for example, M.J. Tobin, M.A. Cohn, M.A.
Sackner: Breathing abnormalities during sleep, Arch.
Intern. Med. 1983; No. 143, pp 1221 to 1228). .
The epidimioloqical significance of sleep apnea is increasingly being recognized; it is known that 2s long and frequent phases of apnea during sleep often accompany cardiovascular and cardiopulmonary diseases as well as extensive psychophysical changes. Effects of sleep apnea include an excessively increased tendency to fall asleep during the day ~in this case sleep apnea is statistically identified as the most frequent cause) and the occurrence of difficulty in falling asleep and sleeping through the night (in this case sleep apnea is described as the fifth most frequent cause (R.M. Coleman, H.P. Roffwarg, S.J.
3s Kennedy: Sleep-Wake Disorders Based on , . . , . ,:, . . .
,, . - ~. , -:' . . .~ . .- ,' , , :
. ' - ' . ; - , - :

Polysomnographic Diagnosis. A National Cooperative Study. JAMA 1982; No. 247, pp. 997 to 1003)).
For some time the study of sleep-wake disorders has been performed in sleep laboratories of special s clinics, in which a diagnosis can be performed by a polysomnographic evaluation during sleep~ These studies are time-consuming and costly; on account of the many parameters that have to be recorded they can be performed only by confining the patient. In 10 addition to the high costs, such confinement has the disadvantage that the patient's sleep is disturbed by strange surroundings. This ~; ;nishes the value of such studies. Consequently, there have been a number of efforts to eliminate the disadvantages of diagnosis 15 when the patient is in confinement.
One possibility is to recognize and diagnose the sleep apnea syndrome in an ambulatory manner with the aid of mobile detection and recording apparatus, thus avoiding confinement in sleep laboratories.
Thus, in European patent application 0,371,424 a method and an apparatus for the ambulatory detection ;~ and diagnosis of the sleep apnea syndrome is ~ described, corresponding to the kind referred to i above. In this method heart potentials are measured 25 relative to a third electrode with two electrodes which are applied to the upper body of a patient and , the measured potentials are fed to a peak level detector. The heart rate is determined by the time intervals between the peak values. The breathing and snoring sounds are picked up by an electret microphone which is applied to the patient's larynx and fed to two different threshold detectors, one threshold ' detector being sensitive over the entire frequency range (about 100 Hz to 15 Xhz) and the other being ' 35 sensitive only in the lower frequency range (about 100 Hz to 800 Hz) on account of the damping of the high . ~ .

: 2063691 frequencies of the signals with a filter. The threshold detectors respond when the applied signal exceeds the preset thresholds. The thresholds are adjusted so that normal breathing is detected by the 5 first-named threshold detector, and snoring is detected with the second detector. These physiological parameters, namely heart rate and the presence or absence of breathing and snoring, are measured together at time intervals of one second, and stored in binary code for each time interval in a RAM
located in the apparatus. The data stored during a period of sleep are transferred from the mobile apparatus to a computer and analyzed on the computer for a sleep apnea syndrome. Information as to the 15 presence of an apnea can be derived from the changes in time of the heart rate and the breathing and snoring sounds and the correlations between these parameters.
The seriousness of an apnea depends on the zo frequency of its occurrences, their severity and their duration. The method using the described apparatus has the disadvantage that it permits only a relatively rough, not very reliable diagnosis of the sleep apnea syndrome. The frequency, but not the severity of 25 apnea episodes can be determined, and their duration only imprecisely, because it is not easy to distinguish between a complete cessation of breathing and a light continued breathing. Information on the ~ position and movements of the patient, which is .. 30 important to the diagnosis, say, to distinguish between obstructive and central apnea, myoclonus and other sleep disturbances, is unavailable. In the case of disease conditions, such as polyneuropathy, geriatric heart or diabetes, the heart rate does not change greatly as it does in apnea attacks, but remains virtually constant. In the presence of such , . , . , ~ . .

.. .
, ... ..

:
. . , - : .

206~691 conditions apnea is difficult to diagnose. In many cases, therefore when the apparatus of the state of the art is used, it must be followed by confinement in a sleep laboratory.
s The invention is therefore addressed to the problem of devising a method for the ambulatory detection and diagnosis of the sleep apnea syndrome, which will offer such great reliability of diagnosis that subsequent confinement in a sleep laboratory for observation will as a rule be unnecessary. In addition to determining the frequency, the method should also permit a quantitative determination of the severity and duration of apnea episodes and should cover the position and ~v~ ents of the patient. A
15 diagnosis of apnea should also be possible in the case of the disease conditions mentioned above; vice versa, if their presence is unknown, indications of these ;~ conditions should be provided. This includes the design of an appropriate apparatus.
This problem is solved by a method for the ambulatory detection and diagnosis of the sleep apnea syndrome, which includes detecting the physiological parameters of a patient comprising heart rate, respiratory sounds and snoring sounds by means of a s mobile apparatus, storing in coded form in the mobile ~,......................................................................... .
apparatus, a plurality of sets of the above parameters ~-obtained during brief intervals, transferring this plurality of sets of parameters to a computer and ~,analyzing them by considering time variations of the individual factors and correlations therebetween, which is characterized by the fact that, in . .
~synchronism with the other parameters determined and ,;recorded, the oxygen saturation of the blood and the bodily position of the patient are determined and ~~3s stored in coded form by the mobile apparatus, the stored sets of these parameters together with those of .

- - - ~ - , ~: -206~91 the other parameters are transferred to a computer and analyzed with the latter, so that a measure of the severity of individual episodes of apnea is obtained in the analysis on the basis of the duration and 5 severity of periods of oxygen desaturation, and on the basis of changes in the bodily position a measure of the sleep disturbance is derived and from that a measure of the soundness of sleep is obtained.
By means of the relationship between the occurrence of apnea episodes and positions of the body it is advantageously possible by the analysis to distinguish between obstructive apnea, central apnea and other sleep disturbances, such as myoclonus, .
bearing in mind that in obstructive apnea the episodes 15 occur more frequently in the supine position.
Generally, an apnea episode leads to an important change of the heart rate and to oxygen desaturation of the blood. If, however, desaturation is observed at a virtually constant heart rate, this can be considered as an indication of a polyneuropathy, geriatric heart, diabetes or a threatened coronary infarction. To ~' improve the quality of the diagnosis, it is advantageous to identify special events which, if undetected, might interfere during the analysis, such ~s 25 as getting in bed, waking up, or standing up. This can be accomplished, in addition to the continuous recording of the body position, by enabling the patient, in such an event, to press a button on the mobile apparatus. By measuring the time frame of the , 30 oxygen desaturation of the blood it is possible to determine the duration of an episode of apnea;
consequently it is not necessary to determine the duration by the respiratory sounds. Instead, it is advantageous to analyze only the violent snoring 3s sounds which occur when gasping for breath after an episode of apnea.
.~

' - ~ ~
r ~1 '' , . ' ' ' ~

20~3691 The apparatus according to the invention for the practice of the above method comprises a mobile apparatus which contains means for detecting the heart rate, the breathing and snoring sounds, the degree of s oxygen saturation of the blood and the bodily position of the patient, at brief intervals of time. Moreover, the apparatus has means for the recording of a number of sets of these parameters in coded form. The apparatus can also have means for the marking of 10 certain detection time intervals, this being preferably a push-button switch. The testing time intervals can be of various length according to the ' different factors to be detected and registered;
intervals of 1 to 10 seconds are preferred. In the case of another preferred embodiment, shorter intervals of as little as 0.1 sec can be used. In another embodiment, the length of the detection time intervals is variable, and the length can be set automatically as needed by the mobile apparatus.
Especially short time intervals are then selected by - the apparatus when an especially noteworthy event occurs, i.e., a possible episode of apnea.
The means for measuring the oxygen saturation of the blood include at least one light source and at 25 least one light receiver, which are fastened to an extremity of the patient and serve for measuring the light absorption or reflection produced by the extremity. The light source or sources can be a light-emitting diode or diodes and the receiver or receivers can be a phototransistor or phototransistors. The wavelength of the light is preferably selected such that the change in the blood color associated with a change in the oxygen content of the blood can best be detected; this is the case in 3s the red-light range. If light of two different wavelengths is used, the second light radiation used 206~691 is preferably selected so that its reflectivity or transmissivity are as independent as possible of the oxygen content of the blood; this is the case in the infrared light range. The light of the second s wavelength serves to obtain a reference level independent of the oxygen content by which the transmitted or reflected light that is sensitive to the oxygen content can be standardized. If the measurement of the color change is based on absorption, the light source or sources and light receiver or receivers are preferably disposed opposite one another on a mounting, with the light emitting and ~light receiving sides of the light source or sources iland light receiver or receivers, respectively, facing ;15 each other. In a preferred embodiment, the mounting is a clip, the light source or sources and light receiver or receivers being disposed on confronting legs of the clip. In another preferred embodiment, the mounting is a flexible strip which is bent into a U-shape at one end, the light source or sources and light receiver or receivers being fastened to the limbs of the U. In both embodiments the mounting is fastened to the patient's extremity so that the body tissue is situated between the light source or sources 2s and light receiver or receivers.
The means for detecting the patient's position ~ preferably contain a hollow body to be fastened to the patient's upper body, with a ball of electrically conductive material inside it. The hollow body is -~ 30 advantageously a hollow tetrahedron at whose corners are provided electrical contacts which can be closed by the ball. The hollow tetrahedron can, for example, - be so oriented that, in the supine position, lying on the left and right side, and in the upright position, 35 the ball will come to rest in one of the corners where it closes the contact. In the prone position the ball ,, .
, . , : :: ..,;
..

lies on a surface of the tetrahedron and makes no contact.
Advantageously, the means for the analysis of ! respiratory sounds are arranged such that they detect s only the heavy snoring sounds produced by gasping for air after an episode of apnea. This can be accomplished by raising the threshold of the detector that is sensitive over the entire frequency range.
The devices provided for the detection of the patient's heart rate, breathing and snoring sounds, degree of oxygen saturation of the blood and bodily position are fastened to the patient's body and preferably connected to the mobile apparatus by signal wires. In another preferred embodiment, the signals 15 from these devices are transmitted to the mobile apparatus wirelessly, e.g., by electromagnetic waves.
;; In this case there is no need to fasten the mobile apparatus directly to the patient's body. Instead of ' a push-button on the mobile apparatus for marking 20 special events, a likewise wireless remote-controlled switching device can be used.
As the above statements indicate, the invention ', has the advantage that by measuring the degree of ' oxygen saturation it is possible to determine the . 25 severity of the apnea attacks and thus achieve a quantitatively accurate analysis of the sleep apnea ' syndrome. The detection of the patient's body position permits a determination of restlessness in sleep and a diagnostic distinction between apnea, 30 myoclonus and other sleep disorders. Furthermore, episodes of apnea can be diagnosed also in the '; presence of disorders in which the heart remains virtually constant; the discovery of such disorders is ~' also possible. In general, therefore, in comparison 35 with the state of the art, the invention offers substantially better and broader possibilities for the .. . . : ~ . . . ,,. , , .. , ~ ..... . . . .. .

diagnosis of the sleep apnea syndrome. It has been found that data obtained by means of the method of the invention, using t~e apparatus of the invention, are so very meaningful that, in the case of the great s majority of patients, no further testing was necessary after the data were evaluated by technically trained personnel. In spite of their simplicity, diagnoses can be made with the apparatus according to the invention which are comparable in reliability with those of long-term tests with confinement in sleep ~ laboratories, without the falsifying influences -~ involved during a stay in a sleep laboratory.
An embodiment of the invention will be described with reference to the annexed drawings in which:
Figure l is a perspective view of a mobile detection and recording apparatus;
Figure 2 is a perspective view of the apparatus in working position on a patient's body;
zo Figure 3 is a side view of an oximeter sensor with a stiff finger clamp for detecting the oxygen saturation level by measuring light absorption;
Figure 4 is a side view of another embodiment of an oximeter sensor corresponding to Figure 3, but 25 with a flexible strip instead of a stiff clip; and Figure 5 is a block circuit diagram of the detection and recording apparatus.
The detection and recording apparatus l of Figure l consists of the actual detection and 30 recording unit 2 with a push-button switch 7 on the front, and the following different pickups: three EKG
electrodes 3, a laryngeal microphone 4, an oximeter finger sensor 5, a position detector 6 and two connecting cables 8 and 9 each with a plug.
.. 35 Figure 2 shows how the pickups are positioned on the body of a patient lO.

~., ; ~, :.~, . .: ; , ,: ~ :.

,. , :::

2063~91 The EKG electrodes 3 are commercial disposable electrodes which are fastened to the upper body of the patient 10; two of them measure the heart potential relative to the third electrode. The laryngeal 5 microphone 4 is an electret microphone which is fastened with a strap 24 to the neck of the patient 10 so that it lies against the larynx. The side of the microphone 4 that is in contact with the larynx of the patient 10 is provided with an annular isolating pad and an annular self-adhering disposable bandage.
Figure 3 shows an embodiment of a f inger sensor 5. It comprises two stiff clip legs 11 joined '' together by a flexible bow 29. A compression spring , 15 is disposed on one side of the bow 29 between the legs 11 and presses together the legs 11 on the other side of the bow to grip a finger 14 of the patient 10.
On the upper leg 11 there are two light emitting diodes 12, and on the lower one, two phototransistors 13. Part of the light emitted by the light emitting diodes 12 passes through the finger 14 and is received by the phototransistors 13, and another part is absorbed by the tissue of the finger. This absorption measurement is performed at wavelengths of 660 nm and 925 nm. The absorption of the light of the first 2s wavelength depends very much on the oxygen content of the blood; the absorption of the light of the second wavelength is virtually independent of it.
Another embodiment of a finger sensor 5 is shown in Figure 4. It comprises a flexible strip 30 which is bent into a U-shape at one end. At the end of the free limb 31 of the U there are two light emitting diodes 12. On the other limb there are two phototransistors 13 opposite one another. The U-shape strip 30 is pushed over the tip of finger 14. The 3s finger sensor is held in place by means of one or more straps with hook-and-loop fasteners or disposable 2063691 ~s adhesive tapes. As regards the light used and its ; absorption characteristics, this embodiment is the same as the embodiment shown in Figure 3.
Both of the described embodiments o~ the finger s sensor 5 can be installed easily and in correct position by lay people. The embodiment of Figure 3 permits an especially easy and quick placement, while ~"
the embodiment of Figure 4 offers an especially secure , fixation and, since it exerts no pressure of the ~, 10 finger, it provides good wearing comfort.
The position pickup is fastened to the upper body of the patient 10 with an adhesive ring in a specific orientation indicated by positioning instructions printed on its exterior. The position pickup 6 comprises a hollow tetrahedron containing a ball of electrically conducting material, and electrical contacts which can be closed by the ball are disposed in its corners. The hollow tetrahedron is oriented so that, in the supine position, or lying 20 on the left side or the right side, or in the upright position, the ball will come to rest in one of the corners where it closes the contact. In the prone position the ball rs ~ins on a surface of the tetrahedron and makes no contact. The leads running 2s from the microphone, the EKG electrodes 3 and the position pickup 6 are combined in a single cable 8 which can be attached by a 15-pin plug to the apparatus 2. The finger sensor 5 has its own cable 9 ; to connect it to the apparatus 2 with a 9-pin plug.
The analyzing and recording unit 2 thus has such small ~; ensions (190 x 135 x 45 mm) and such light weight (about 700 g) that it can be carried invisibly on the body by a shoulder belt 25 under the clothing. The unit 2 has on its front side a 15-3s te~ i nal and a 9-terminal receptacle 26 and 27, respectively, into which the corresponding plugs of , ~

the connecting cables 8 and 9 can be pushed and secured with screw fasteners. Beside the push-button switch 7, there are also four light emitting diodes 28 on the unit to check the operation of the unit 2 after s it has been put on. To carry the stored data to a computer, a data transfer cable, not shown, is - provided. Power is supplied either by six small 1.5-volt batteries or by corresponding rechargeable batteries.
~'' 10 The wiring diagram illustrated in Figure 5 shows the signal processinq in the analyzing and storage unit 2. The signals picked up by the - microphone 4 are amplified by an amplifier 16 and distributed in two channels; the signals of one ::, 15 channel are then carried through a filter 17. The ; filter 17 damps signals above 800 Hz with a 12-decibel .~ octave damper. Not shown are the unfiltered branch . and the threshold detectors provided for both channels. The threshold detector which is connected to the filter 17 and is sensitive in the frequency range from about 100 Hz to 800 Hz is set to a medium ,' threshold level such that the signals or normal snoring sounds, but not smooth respiratory sounds, will exceed the threshold. The second threshold 2s detector responding to the entire frequency range from about 100 Hz to 15 Khz is set to such a high threshold level that the threshold is generally exceeded only by the very loud snoring and gasping noises following an apnea attack. The information, "threshold exceeded"
and "threshold not exceeded", constitutes a useful binary value for storage and further processing.
The signals originating from the phototransistors 13 of the finger sensor 5 are first amplified by a signal amplifier 20. Then the oxygen 3s saturation level of the blood is determined and binary-coded in desaturation analyzer 21. The signal levels correspond to the intensities of the light wavelengths emitted by the photodiodes 12 and transmitted through the tissue of the finger 14.
Since the absorption of the shorter wavelength light s depends highly on the oxygen content of the arterial blood, and the longer wavelength light is hardly affected at all by the oxygen content, a measure of the oxygen saturation of the blood can be derived from the signal level of the shorter wavelength light after o standardization to the signal level of the longer wavelength light. An accuracy of up to 2~ is achieved in this manner.
The signals originating from the EKG electrodes 3 are first amplified by an EKG amplifier 18 and then are fed to a heart rate analyzer 19 which determines the heart rate. The determined value of the heart rate is then binary-coded.
The four possible position signals originating from the position pickup 6 are analyzed in a position analyzer 22 and also binary-coded. Not shown in Figure 4 is the push-button switch 7.
All of these parameters are continuously picked up in parallel, coded, and stored successively in sets of parameters that belong together in time in a RAM
2s storage 23 with at least 128 kB storage capacity. The basic scanning interval amounts to 1 second; the oxygen saturation is read every 2 seconds, and the body position is read every 10 seconds, and renewed.
The recording time amounts to at least 22 hours. The 30 stored data for a recording period can be transferred via a modem not shown, with a transmission rate of 9200 baud, through an RS232 port of an XT or AT
personal computer not shown. By using memory chips of greater capacity, a total storage capacity of several 35 megabytes can also be achieved. In this way shorter scanning intervals or longer total recording times can be established.
When starting up at the beginning of a recording period, the attacl- ?nt of the connecting ~~ 5 cable 8 to the unit 2 automatically initiates a self-test. It lasts S minutes and is performed with the aid of the light emitting diodes 28. One of the diodes 28 is provided for checking the EKG function, the saturation measurement and the two respiratory sound channels. The light emitting diode associated with ; the EKG channel will light up upon the detection of an ~- R wave and if the operation is correct it blinks in synchronism with the R waves. The light emitting diode associated with the oxygen saturation channel 15 lights during the first 30 seconds of the self-test if no valid value is present; this is the case, for example, if the finger sensor is not fastened to the finger in the correct position. If the operation is correct this diode r~ ~ins out. The two light 20 emitting diodes associated with the respiratory sounds light up when the threshold is exceeded. If the operation is correct, these two diodes remain out in the normal state and can be made to light up by simulating snoring noises or very loud breathing ' 25 noises. After the self-test, the unit 2 begins the detection and storage of the above-mentioned physiological data for the duration of a data recording period.
At the end of a data recording period the data 30 stored in the mobile unit 2 can be transferred to a computer for evaluation. In the evaluation the data can be processed and displayed in three different ways:
i) The measured parameters (respiratory sounds, 35 heart rate, oxygen saturation, body position) are represented together graphically as a function of time 2063~91 ' for the entire period of study. This graph shows quantitatively the common progress of these parameters with time and thus especially also the correlations among them. It has the advantage of containing all of ; s the recorded information; interpretation, however, requires a certain amount of time.
ii) Some parameters are combined with time and are represented in the form of histograms and tables.
For example, a graphic representation of the distributions of the measured heart rates at successive lO-minute intervals, a graphic ; representation of the distribution of the measured oxygen saturation levels, and representation of the desaturation levels as a function of the frequency of their occurrence, in the form of diagrams and tables.
These representations no longer manifest the total development in time and all correlations between the measured parameters, but they do permit a faster interpretation.
iii) The number of episodes in which apnea was probably involved is directly determined from the data and expressed as the so-called RD index (respiratory disturbance index) as the episodes-per-hour unit.
Three such RD indexes are provided: the snoring index, 2s the heart rate variation index and the oxygen desaturation index.
For computation of the snoring index, pauses between snores, which last between ll and 60 seconds, are counted over the entire ex~;n~tion period and divided by the number of hours of the examination period. Pauses of this length are typical of apnea episodes.
To determine the heart rate variation index, first a relative heart rate is computed by dividing 3s the momentary heart rate by the running average of the heart rate of the previous 300 seconds. Relative : . : .. .. .
-: . . ~ :: ........... :: , -: ,, .:: . : ~
.. . ..

i - 16 -20~3~91 heart rate frequencies between 90% and 109% are associated with the so-called 100% class; other frequencies are outside of this class. The heart rate : variation index gives the number of events in the test ~' 5 period in which the relative heart frequency leaves the 100% class and returns to it within 11 to 60 seconds, divided by the number of hours in the test - period. Thus, the heart rate variations are analyzed as they occur in synchronism with the apnea episode.
10To determine the oxygen desaturation index, first the basal saturation level is determined by ' adding the highest oxygen saturation values from 2 to 10 preceding measurements, and the sum is divided by the number of measurements. A desaturation phase is present when the saturation level decreases by at least 3% from the basal saturation level and lasts until 90% of the basal saturation level is reached again after the decrease. The oxygen desaturation index gives the number of desaturation phases in the zo test period divided by the number of hours in the test period. It detects the desaturation phases as they occur, also in synchronism with the apnea episode.
These RD indexes directly give the number of apnea episodes per hour. Normally the three RD
;2s indexes give approximately the same value. Large differences between the three RD indexes can indicate the presence of special disorders, as mentioned in the beginning. Overall, the determination of the three RD
indexes provides an extremely quick and significant judgment of the apnea event.

, . .

Claims

1. Mobile apparatus for detecting and storing physiological parameters in a patient for use in diagnosing the sleep apnea syndrome comprising:
a) means (4) for sensing respiratory sounds and b) snoring sounds, c) means (5) for sensing and storing in coded form the degree of oxygen saturation of the blood and d) means for storing a plurality of sets of parameters a) to c) obtained for short time intervals, in coded form, characterized in that the mobile apparatus further comprises e) means (3) for detecting heart potentials and sensing the heart rate based on the heart potentials and f) means (6) for sensing and coded storage of the bodily position of the patient (10).

2. The mobile apparatus according to claim 1, characterized in that it furthermore comprises means for the identification in coded form of certain time intervals during which parameters a) to e) are detected.

3. The mobile apparatus according to claim 2, characterized in that the means for the identification of certain time intervals include a push-button switch (7).

4. The mobile apparatus according to any one of claims 1 to 3, characterized in that the means for sensing the degree of oxygen saturation of the blood include a sensor with at least one light source (12) and at least one light receiver (13) for measuring light absorption or reflection produced by an extremity (14) of the patient.

5. The mobile apparatus acceding to claim 4, characterized in that the light source (12) and the light receiver(s) (13) are oppositely disposed on a fastening means, the light emitting and light receiving side of the light source (12) and light receiver (13), respectively, facing one another.

6. The mobile apparatus according to claim 5, characterized in that the fastening means is formed by a clip (5), said light source(s) (12) and light receiver(s) (13) and light receiver(s) (13) being disposed on opposite legs (11) of the clip (5).

7. The mobile apparatus according to claim 5, characterized in that the fastening element is formed by a flexible strip (30) which is bent U-wise at one end, said light source(s) (12) and light receiver(s) (13) being disposed on limbs of the "U".

8. The mobile apparatus according to any one of claims 1 to 7, characterized in that the means for detecting the bodily position of the patient include a hollow body (6) to be fastened to the upper body of the patient (10) with a ball of electrically conductive material situated therein.

9. The mobile apparatus according to claim 8, characterized in that the hollow body (6) is a hollow tetrahedron in whose corners electrical contacts are disposed which can be closed by the ball.

10. The mobile apparatus according to any one of claims 1 to 9, characterized in that the means for the detection of the respiratory and snoring sounds are arranged such that they pick up only loud, snoring sounds resulting from gasping for air after an episode of apnea.